Erect or pendulous epiphytic herbs. Stems either short with few leaves close together, or rather long with many well-spaced leaves. Leaves narrow, usually oblong, flat or conduplicate. Racemes axillary; bracts distichous or spiral. Flowers opening successively, short lived; rarely opening together and long lasting; sepals and petals subequal, ovate to elliptic; lip continuous or jointed to foot of column, concave or saccate at base, 3-lobed, lobes erect from foot of column forming an enclosed sac-like structure, lateral lobes falcate, erect, embracing column, midlobe fleshy, with various trichomes and callosities on disc; column stout, with a distinct broad foot; anther terminal, operculate; pollinia 4, in 2 groups, each divided into unequal halves, or 2 and distinctly sulcate, waxy, attached to a large, broad stipe; stigma entire. Capsules linear-cylindrical.
About 120 species, from Sri Lanka, Malaysia, the Philippines and Indonesia to Samoa and Papua New Guinea. Nine species in Taiwan.